5 6 Hcemajlatics. 
the Qiiantlty of Blood thrown out of the left 
Ventricle in a given time, bears to the Quan- 
tity which can pafs thro* the capillary Arteries 
into the Veins, in that time. 
II. But the Refiftance which the Blood 
meets with in thofc capillary PalTages, may be 
greatly varied, either by the different Degrees 
of the Vifeidity or Fluidity of the Blood, or 
by the fcveral Degrees of Conffridion or Re- 
laxation of thofe fine Vcflels ; Inftances of 
which may be feen in Experiments XV, XVI, 
XVII, XVIII. 
22. And as the State of the Blood or Blood- 
veficls arc in thefe Refpefts continually vary- 
ing from divers Caufes, as Motion, Reft, Food, 
livacuations, Hear, Cold, fo as proba- 
bly never to be cxadly the fame, any two 
Minutes, during the whole Life of an Ani- 
mal ; fo nature has wifely provided, that aeon- 
flderable Variation in thefe, fliall not greatly 
difturb the healthy State of the Animal. 
23. We may make a pretty near Eftimate 
of the Force of the Blood in the capillary 
Vcfi'cls in the following manner, viz. taking 
the Diameter of a Blood Globule to be as 
above 7“ch part of an Inch ; which Leev;en- 
hoek has obferved tp be of the fame Size both 
m 
